Do not log compilation informational messages.

Bug: https://curl.haxx.se/mail/lib-2016-07/0070.html
Reported-by: Paul Howarth

As SPNEGO is only defined when these pre-processor variables are defined
there is no need to query them explicitly.

Typo introduced in commit ad5e9bfd.

... and make the distros link a proper link

Embedded manifest option didn't work due to typo.

Reported-by: Stefan Kanthak

This is a follow up to the parent commit dcdd4be3 which fixes one leak
but creates another by failing to free the credentials handle if out of
memory. Also there's a second location a few lines down where we fail to
do same. This commit fixes both of those issues.

This patch allocates memory to "output_token" only when it is required
so that memory is not leaked if function returns.

Follow-up commit to c5098080 to make this test pass.

- Linux TFO + TLS is not implemented yet.

Bug: https://github.com/curl/curl/issues/907

- Curl_ipv6works() is not thread-safe until after the first call, so
call it once during global init to avoid a possible race condition.

Bug: https://github.com/curl/curl/issues/915
PR: https://github.com/curl/curl/pull/918

Closes https://github.com/curl/curl/pull/914

Closes https://github.com/curl/curl/pull/913

Closes https://github.com/curl/curl/pull/911

Explain how some FTP servers support the machine readable listing
format MLSD from RFC 3659 and compare it to LIST.

Ref: https://github.com/curl/curl/issues/906

Closes #892

Closes #896

Reported-by: Gou Lingfeng
Bug: https://curl.haxx.se/mail/lib-2016-06/0139.html

Reported-by: Richard Gray
Bug: https://curl.haxx.se/mail/lib-2016-06/0136.html

- the expression of an 'if' was always true
- a 'while' contained a condition that was always true
- use 'if(k->exp100 > EXP100_SEND_DATA)' instead of 'if(k->exp100)'
- fixed a typo

Closes #889

... as otherwise we could get a 0 which would count as no error and we'd
wrongly continue and could end up segfaulting.

Bug: https://curl.haxx.se/mail/lib-2016-06/0052.html
Reported-by: 暖和的和暖

... as previously the README.cmake would be picked and put at the bottom
of the docs page there and it wasn't very representative!

rawgit.com asks to use the domain cdn.rawgit.com for production

See #900

Closes #740